/*
 * @project        The CERN Tape Archive (CTA)
 * @copyright      Copyright(C) 2003-2021 CERN
 * @license        This program is free software: you can redistribute it and/or modify
 *                 it under the terms of the GNU General Public License as published by
 *                 the Free Software Foundation, either version 3 of the License, or
 *                 (at your option) any later version.
 *
 *                 This program is distributed in the hope that it will be useful,
 *                 but WITHOUT ANY WARRANTY; without even the implied warranty of
 *                 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *                 GNU General Public License for more details.
 *
 *                 You should have received a copy of the GNU General Public License
 *                 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#pragma once

/**
 * Abstract class used as a base class for the disk/tape write file tasks. The data consumer
 * has two methods: "pushDataBlock" used to put in the consumer's fifo a new full memory block
 * to consume, and "getFreeBlock" used by client code two reclaim the consumed memory block.
 */
namespace castor {
namespace tape {
namespace tapeserver {
namespace daemon {
  
// Antcipated declaration to hasten compilation
class MemBlock;

class DataConsumer {
public:
  
  /**
   * Returns used (consumed) memory blocks.
   * @return the memory block to be reclaimed
   */
  virtual MemBlock * getFreeBlock() = 0;
  
  /**
   * Inserts a new memory block in the consumers fifo.
   * @param mb memory block to be inserted in the consumer fifo and consumed
   */
  virtual void pushDataBlock(MemBlock *mb) = 0;
  
  /**
   * Destructor
   */
  virtual ~DataConsumer() {}
};

}
}
}
}